add an excercise to proxys

oop/design_patterns/design_patterns/Car.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace design_patterns
+{
+    class Car : ICar
+    {
+        public void MoveCar(Driver _driver)
+        {
+            Console.WriteLine("I'm driving...");
+        }
+    }
+}

oop/design_patterns/design_patterns/Driver.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace design_patterns
+{
+    class Driver
+    {
+        public int age { get; set; }
+
+        public Driver(int s)
+        {
+            this.age = s;
+        } 
+
+    }
+}

oop/design_patterns/design_patterns/ICar.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace design_patterns
+{
+    interface ICar
+    {
+        void MoveCar(Driver _driver);
+    }
+}

oop/design_patterns/design_patterns/Program.cs

@@ -20,6 +20,22 @@ namespace design_patterns
             EagerSingleton.Instance.value = "Hello from EagerSingleton";
             Console.WriteLine(EagerSingleton.Instance.value);
             Console.ReadKey();
+            Console.WriteLine("--------");
+            Console.WriteLine();
+            Console.WriteLine();
+            Console.WriteLine();
+            Console.WriteLine("Proxys");
+            Console.WriteLine("--------");
+            Driver max = new Driver(17);
+            Driver heinz = new Driver(12);
+            ProxyCar ferarri = new ProxyCar();
+            Console.WriteLine("Let max drive");
+            ferarri.MoveCar(max);
+            Console.WriteLine();
+            Console.WriteLine("Let heinz drive");
+            ferarri.MoveCar(heinz);
+            Console.ReadKey();
+
         }
     }
 }

oop/design_patterns/design_patterns/ProxyCar.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace design_patterns
+{
+    class ProxyCar : ICar
+    {
+
+        Car realCar = null;
+
+        public void MoveCar(Driver _driver)
+        {
+            if (realCar == null)
+            {
+                realCar = new Car();
+            }
+            Console.WriteLine("The proxy is checking the driver age.");
+            if (_driver.age > 16)
+            {
+                Console.WriteLine("Check passed.");
+                realCar.MoveCar(_driver);
+            }
+            else
+            {
+                Console.WriteLine("You're not old enough");
+            }
+        }
+    }
+}

oop/design_patterns/design_patterns/design_patterns.csproj

@@ -42,10 +42,14 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Driver.cs" />
     <Compile Include="EagerSingleton.cs" />
+    <Compile Include="ICar.cs" />
     <Compile Include="LazySingleton.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Car.cs" />
+    <Compile Include="ProxyCar.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="App.config" />